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Bend spoke on rear wheel
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So I was dumb enough to forget I changed rear derailleur limits and put the wheel back in and ride. As you can imagine 20 minutes into the ride rear derailleur send the chain between the casette and the spokes. I removed the casette to free the chain and noticed the force has bend 3 spokes slightly at the point they are connected to the hub. The ones in the photo are the most severe ones. Wheel is true, spokes have the same tension. How safe is this?
Its a Roval CLX 40 rear wheel.
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Re: Bend spoke on rear wheel [swimfan] [ In reply to ]
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Me ? If that was my wheel ? With my weight ? (>200lbs in my lazy covid no races state) ?
I'd swear and cuss a bit. Then carry on as normal.

They don't look chewed up (notches / gouges are where stresses increase more notably and they don't appear like that) and in reality 95% of the time spokes really break at the nipple end / in the threads (as that is where the reverse bending stresses are worst on the spoke).

I'm sure I've run MTB wheels with a whole lot more damage for ages.
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Re: Bend spoke on rear wheel [swimfan] [ In reply to ]
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As there's a bend then that has changed the length of the spoke, and so the tension. Which means if the wheel is still true, something else is also making an equal and opposite change if that rim is still true.

And it's true that the bend here is in a location that doesn't normally have stress focuses (bends and threads) but that tension change will be doing something somewhere. At some point then you are going to end up pinging spokes. May not be for a while, but it will happen.

If you get it into a shop now, then it should just be a case of those 2/3 spokes needing replacing and a minor retrue - the other spokes will be ok. What tends to happen if you ride like this for a while then one will break, you'll replace that then 2 weeks later another will go that has been taking the additional load. Etc etc. And you end up with a bigger job.

So really it depends on the wait at the bike shop. I'd not be afraid to ride it if there's a month wait, but be aware you may be up for a full set of new spokes and a rebuild. It won't kill you and it's highly unlikely it'll leave you stranded on a ride.
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Re: Bend spoke on rear wheel [swimfan] [ In reply to ]
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Piano wire is insanely strong. I wouldn't worry about. Like said, breaks occur at the nipple. Bends are minor.
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Re: Bend spoke on rear wheel [Duncan74] [ In reply to ]
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It's not necessarily shorter. It may have just yielded locally to 'allow' the bend. It could in fact be even stronger in that area from the work hardening.
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Re: Bend spoke on rear wheel [BobAjobb] [ In reply to ]
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BobAjobb wrote:
It's not necessarily shorter. It may have just yielded locally to 'allow' the bend. It could in fact be even stronger in that area from the work hardening.

I didn't say shorter, indeed if it's bent it has to be longer as it's not in a straight line. And the suggestion it's stronger due to work makes no logical sense as if that were to be the case then all top spec wheels would come with kinks in the spokes 2" from the hub deliberately made to add strength..... Clearly the stresses here have exceeded the elastic limit of the spoke and it's gone to within it's plastic limit. Which has increased the length of the spoke slightly. Possibly by amazing luck the bend and the length increase from the plastic deformation have offset to result in the same tension on the rim which is why it's still true. However, as you ride and that spoke is at the bottom, the loads reduce the spoke tension, and then when that spoke is at the top of the wheel it's tension is slightly greater. Every rotation then the spoke tensions increase and decrease. So that means that the spokes are back to behaving in the elastic range. Sadly once a metal is cold formed (ie through being bent by a derailler / chain) then the high cycle fatigue is reduced. Added to that the differing lengths of spokes now means that the other spokes are going to take more load and so be further into their elastic range each rotation which ultimately reduces life.

Unless you are really meaning specifically strength as opposed and as a tradeoff to durability which is exactly the point I was making - the life of the spokes will be reduced - most likely not this spoke but others either side or 180degrees round the wheel.


And so back to the OP - carry on riding if you want, but sorting now takes the worry away from you waiting for the spokes to start pinging which they certainly will do earlier than if you hadn't done that. May be in the next week, next month or 2 years away. But sorting now will need one or two spokes. Leave it until it does ping will put you on a slope to changing all the spokes.

(FWIW then I started my own wheel building about 20 years ago when commuting 30 miles a day with a heavy bike and panniers with laptop, work clothes, gym kit. You couldn't avoid hitting a pothole every now and again and so spokes would go, wheels need re-truing. And I couldn't manage to wait for the delay of bike shops, so learnt to do it myself using the Sheldon brown website instructions).
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Re: Bend spoke on rear wheel [swimfan] [ In reply to ]
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I'd personally replace all of the damaged spokes and put in new nipples while I was at it. Nipples are cheap so it would give me piece of mind to do so. Not necessary as they are pretty robust if they are brass. Aluminum nipples I wouldn't reuse though.

But, I also fix it myself because I took time to learn how to wheel build so have both the tools and the know-how. If you want to learn a great resource is the Roger Musson book. It's wheel building 101 with plans included on how to build your own wheel truing stand and dish tool for cheap.
Last edited by: loxx0050: Jun 27, 20 16:32
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